Support deps files with no output

AIDL generates a deps file with no output listed temporarily pass it
through without error in the makedeps parser.

Bug: 141372861
Test: m checkbuild
Change-Id: I8c6740833dbc2ff3318dfc424ec497728cfc48d2

makedeps/deps_test.go

@@ -147,6 +147,20 @@ b: e`,
 				},
 			},
 		},
+		{
+			// TODO(b/141372861): remove this
+			// AIDL produces a dep file with no output file for a parcelable (b/
+			name: "AIDL parcelable",
+			input: ` : \
+  frameworks/base/tests/net/integration/src/com/android/server/net/integrationtests/HttpResponse.aidl
+`,
+			output: Deps{
+				Output: "",
+				Inputs: []string{
+					"frameworks/base/tests/net/integration/src/com/android/server/net/integrationtests/HttpResponse.aidl",
+				},
+			},
+		},
 	}
 
 	for _, tc := range testCases {